ROCHESTER, NY — July 21, 2005 — Mpower Communications Corp. (AMEX:MPE), a leading provider of data and voice services to retail and wholesale business customers , will host a conference call to discuss the details of its second quarter 2005 financial and operating results.

Date: Thursday, August 4, 2005

Time: 10:00 a.m. (Eastern time)

Webcast & AudioStreaming Link/Instructions:

PLEASE NOTE: The URL for the web cast has changed to:

http://showvisuals.mshow.com/findshow.aspx?usertype=0&cobrand=128&shownumber=249277

This link will access both the audio and PowerPoint presentation for the call. Advanced registration on the site is recommended. Click on the link above to register in advance and/or join the conference call at the designated time.

Webcast Replay: Available for 30 days after the call at above link

Audio Live Number: 1-800-322-0079

Audio Replay Number: 1-877-519-4471, PIN #6295859

From Thursday, August 4, 2005 at 1:00 p.m. Eastern through Thursday, August 11, 2005 at 5:00 p.m. Eastern

About Mpower Communications
Founded in 1996, Mpower Communications (AMEX:MPE) is a leading facilities-based broadband communications provider offering a full range of data, telephony, Internet access and Web hosting services for retail business and wholesale customers. Further information about the company can be found at www.mpowercom.com.